Sir Alex Ferguson insists it will take a freakish run of good luck for it to happen.
But Tottenham boss Harry Redknapp is prepared to put his money on Manchester United ending the season with an unprecedented haul of five major trophies.
Sunday's penalty shoot-out win over Redknapp's Spurs in the League Cup final means it is two down, three to go for United following their World Club Championship triumph in Japan in December.
And the next ten days will go a long way towards deciding the fate of their bid for a clean sweep of every competition they have entered this season.
Liverpool's defeat at Middlesbrough on Saturday means Ferguson's men, who travel to Newcastle on Wednesday, are seven points clear in the Premier League with a game in hand.
An FA Cup quarter-final tie at Fulham on Saturday could see United move to within two matches of claiming that trophy and, four days later, Inter Milan visit Old Trafford with a place in the last eight of the Champions League at stake.
By mid-March, the odds on a 'quintuple' could be very much shorter, but Ferguson insists he is not getting "carried away" by the prospect of an achievement that would match that of one of his heroes, Jock Stein, with Celtic in 1967.
"Only you guys, the media, will get carried away with it," he said. "We'll keep our feet on the ground.
"My experience is we could go to Fulham this weekend in the FA Cup and the ball comes off somebody's backside and we are out of the cup. That is what cups can do to you."
"The best thing we can do is gather ourselves, energise ourselves for Newcastle on Wednesday, which will be a very difficult game for us, and go from there, taking it one step at a time."
Redknapp has been around long enough to share Ferguson's scepticism about the chances of everything turning out just as you would like it.
But he also believes United's squad has sufficient depth of quality to make their own luck.
"They have got a big chance -- they are the team to beat for sure," Redknapp said.
"They have a fantastic squad. They have one cup already, it looks as if the league is going their way for sure and you wouldn't bet against them in the Champions League and the FA Cup."
Ferguson acknowledged that Tottenham might easily have won Sunday's match before the shoot-out but for the heroics of goalkeeper Ben Foster, who made crucial saves in open play from Aaron Lennon and Darren Bent before stopping Jamie O'Hara's opening spot-kick for Spurs.
"It was not an easy day for us," Ferguson said. "Tottenham were good opponents and they probably had the better chances in the match but Ben has made a few good saves for us."
Ferguson said Foster's performance was another sign that, as well as being the natural successor to Edwin van der Sar at United, he could go on to be England's number one for "a large number of years."
"The future is his," Ferguson added. "The present belongs to Van der Sar, that is obvious but that performance can only strengthen my opinion of his ability and his own self-confidence.
"He is a strong character -- he has had to be. He has had to come through two cruciate ligament injuries and you have to have something inside you to do that."
Despite his admiration for United, Redknapp felt his side had edged the contest on points.
"The lads were terrific, we just could not get that break," he said. "I thought we were going to win it in the last minute (when Darren Bent drew a good save from Foster)."
Spurs' fate was sealed after O'Hara had their first penalty saved by Foster and David Bentley steered the third spot-kick wide, handing Brazilian midfielder Anderson to follow Ryan Giggs, Carlos Tevez and Cristiano Ronaldo in converting his spot-kick to give United an unassailable 4-1 lead.
Despite Ferguson's praise for Tottenham's display, it was United who came closest to winning the match in regulation time with Ronaldo having struck the inside of the post in the third minute of injury time.
Television replays also suggested that Ronaldo should have earned a penalty earlier in the second half after beating Ledley King to the ball inside the box.
Instead the Portuguese winger earned a yellow card for what the referee judged to have been a dive.
Tottenham's best chance fell to Lennon soon afterwards but the winger was unable to beat Foster from ten yards.